/*
 * Copyright 2002-2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.config;

import org.springframework.lang.Nullable;

/**
 * SingletonBeanRegistry主要是用于管理单例的注册、获取。
 *
 * @author Juergen Hoeller
 * @see ConfigurableBeanFactory
 * @see org.springframework.beans.factory.support.DefaultSingletonBeanRegistry
 * @see org.springframework.beans.factory.support.AbstractBeanFactory
 * @since 2.0
 */
public interface SingletonBeanRegistry {

	/**
	 * 注册单例
	 */
	void registerSingleton(String beanName, Object singletonObject);

	/**
	 * 根据名称获取单例对象
	 */
	@Nullable
	Object getSingleton(String beanName);

	/**
	 * 是否包含某个bean的单例
	 */
	boolean containsSingleton(String beanName);

	/**
	 * 获取单例的bean名称数组
	 */
	String[] getSingletonNames( );

	/**
	 * 获取单例的个数
	 */
	int getSingletonCount( );

	/**
	 * 返回此注册表使用的单例互斥对象，用于锁（Synchronize）
	 */
	Object getSingletonMutex( );

}
